Airplane carburetor



Sept. 14 1926. 1,600,008

F. C. MOCK AIRPLANE CARBURETOR Filed Jan. 16 L924 Patented Sept. 14, 1926.

UNITED STATES 1,600,008 PATENT OFFICE.

FRANK C. EDGE, OF CHICAGO, ILLINOIS, ASSIGNOR TO STROIYIBERG MOTOR DEVICES 00., OF CHICAGO, ILLINOIS, A CORPORATION OF,ILLINOIS.

Amman CARIBURETQR Application filed January 16, 1924. seven No. 686,474..

My invention relates to carburetors, particularly to air lane carburetors or others' in which there 1s a plurality of carburetor barrels or mixture outlets each "controlled by a' throttle valve. The invention is applicable Where a. number of individual carburetors are provided to serve an engine or where a carburetor structure is provided having, a number of barrels each connected to serve one or more of the engine cylinders.

Under such conditions of operation it is very desirable that the throttle valves be closely fitted and operate in close synchronism, because ifv 'the throttle valve for one set of cylinders be wider open than the throttle valvefor another'set, it will cause the former set er cylinders to speed up the motor and over run the other. During idling the manifold ressure 1s general] less than .52 of atmosp eric presd conse uently the rate of airfiowing past the thrott e is the atmospheric velocity of sound and is independent of changes in engine speed or manifold vacuum so long as this manifold pressure is less than .52 of the atmospheric pressure. Thisv means that the air flow through the throttle crack is independent of the engine speed, and if theengine is caused to speed up to 600 R. P. M. by one throttle being unduly open while the remaining throttle or throttles are,

at a position corresponding to 300 R. P. M),

these remaining cylinders will receive an air charge onl one-half that of normal idling, under w ich condition their charges will either not ignite at a1 l,.or will burn so slowly that flame will be thrown out of the cylinders when the exhaust valves open.

The object of my invention is, therefore, to rovide simple and efficient means for insurmgaccurate synchronous adjustment of the throttle valve;

On the drawings Figure 1 is a plan view of a double barrel carburetor; Fig. 2 isa sectional'view on plane 2-2 of Fig. 1 of the u per part of one barrel;

Fig. 3 is a detai elevational viewof the secsor gears connecting the throttle shafts; an

Fig. t-is a detail sectional view of one ofthe ears, illustrating its eccentric mounting on. t e throttle shaft.

On the drawings, 10 represents the bodyrespectively, with the throttle valves 13 and 14. The valve 13 is secured on the shaft 15 extending diametrally through the barrel 11 and the valve 14 is secured on the shaft 16 extended diametrally through the barrel 12 and parallel to theshaft 15.

It is first necessary that an adjustment be provided so that the throttles can seat at the same time regardless of small inacouraeies of the connecting means for transmit ting operative motion from one throttle to the other. In the present instance this motion transmitting means comprises a gear sector 17 on throttle shaft 15 and a companion gear sector 18 on the throttle shaft 16. Each gear is formed with a split hub 19 adapted to be clamped to its shaft by a ings of the sector gears permitof easy adscrew or bolt 20. These split hub mountthrottle shafts so that both throttles can be readily adjusted to seat at the same time. The percentage of variation in mixture flow between the'two carburetor barrels as a re sult of mechanical inaccuracies is greater at small throttle openin s than at large, and it is therefore desirable urin small throttle openings that the two throttles follow each other in very close synchronism. I have therefore arranged that during small throttle openings the sector gears 17 and 18 transmit a fine control between the throttles by virtue of a close mesh between the gears. I have found, however, that if these gears are meshed tight enough to give the requisite fine control at small throttle openings, they are very apt to stick or jam at other throttle openings. In addition, this fine'control is very difficult to achieve in ordinary methods of manufacture. To avoid these difficulties I have interposed between one of the sector gears, such as the gear 17, and its respective throttle shaft 15, an eccentric bushing which permits of fine adjustment of the two gears to the end of obtaining a close accurate mesh during the low idling positions, and a looser mesh during the relatively wide openings of the throttles. This eccentric bushing is indicated at 21 and has an outer hexagonal head 22, by which it may be readily rotated in the split hub of the gear. The eccentrie bushing and its hexagonal end 22 are also s lit so that the clamping pressure .exerte by the hub 19 will clamp the eccentrio in the gear to the throttle shaft 15. it will be apparent that by slight rotation of this eccentric bushing the sector gear 17 can be adjusted so that it will have a very close mesh with the other gear 18 during low idling positions or" the throttle, and a relatively looser mesh during open positions of the throttles. (In twelve cylinder motors where several carburetors are employed, smooth operation ol the motor at low speeds can only be secured with the utmost accuracy in the lit of the carburetor throttles and in the relative synclu'onization with each other. I have found that if the gear sectors have any tendency to stick or move hard in certain positions, the operating rods and levers inevitably twist or slip slightly so that this synchroniz tion cannot be main tained, and it is a pi nounced advantage to have the eccentric adjustability of the gears, as above described, so that they can, be set to move freely and not bind in any position.

As shown in l the throttle shaft 15 of the throttle valv extended beyond the carburetor hilt the sector gear respectively, and t rovided wit knurled ends 23 upon w h are adapted to be mounted the menu control lever and the control lever for "tiring together two or such carburetors, two are employed. The other throttle shalt extends through hard metal bushing 24: in the rear wall of the car buretor barrel and is threaded for receiving cap 25. The inner face of this cap is recessed to receive a compression. spring which bears against tl it the bushing 24- and places an end t rust on the throttle shaftto hold it firmly against vibration.

I thus provide simple and eificient means for insuri. g easy, smooth and synchronous operation of the throttle valve and li claim as tollowsz 1. in a carlmretor, the combination of a pair of carburetor barrels, individual throttles in each. of said barrels, gears operatively connecting said throttles, and eccentrio means for adjusting the mesh between said gears 2-. In a carburetor, the combination of a pair of carburetor barrels, individual throttles in each of said barrels, and gears connecting said throttles, said gears being arranged ior a relatively tight mesh in one position of said throttles and a relatively reo ooslooser mesh in another position. (it said throttles.

3. in a carburetor, the combination of a pair of carburetor barrels, individual throttle valves in each of said barrels, individual shafts for operation of said throttles,

gears on each of said shafts meshing to-' between said shafts and operable to cause simultaneous movement of said throttle valves, and means for causing the r axes to move closer together when said throttle valves are moved to one position.

6. lln a carburetor, the combination of a pair of carburetor barrels, a throttle valve in each barrel, a shaft for each throttle valve, said shat-ts being parallel, intermesliing gears connecting said shafts, and means for causing the gear axes to move closer together when said gears are operated to move said valve to closing position.

'7. In a carburetor, the combination of a pair of carburetor barrels, a throttle valve for each barrel, a shaft for each throttle valve, said shafts being parallel, a gear train between said shafts, and means for gradually reducing lost motion, between the rs of said train when said train is operated to move the valves to closed position.

8. ln a carburetor, the combination. of a pair of carburetor barrels, a throttle valve in each barrel, a supporting shaft for each valve, gears connecting said shafts, and means for causing said gears to move ually into closer mesh as the valves move to idling position.

In witness whereof, I hereunto subscribe my name this 5th day of January, 1924..

G. M9 CK.

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